This invention generally relates to crop harvesters and, more particularly, to an improved, flexible belt conveyor which may be used for moving harvested grain from one level in the combine harvester to a higher level. This invention is particularly useful in a drag conveying apparatus in which the material to be conveyed is trapped between a floor and the conveyor belt assembly to effect the upward transport of the material by dragging it up the incline. This is in contrast to the more common method of conveying where the transported material is carried on the upper portion of the belt. It also is useful in hay balers for the formation, containment and compaction of the cut hay into large cylindrical bales.
Drag conveyors as are known in the prior art are composed of mechanical chains with metal crossbars traversing the open distance between the chains. These chains are composed of a multiplicity of parts, including plates, pins, brackets and miscellaneous linkage parts. These mechanical chain conveyors suffer from a number of problems deriving from the many parts involved in the chain configuration. These mechanical chains are subject to stretching due to wearing and elongation of the holes through which the link pins or other fastening means are located. Over a relatively short period of operation of the harvester, the mechanical chain will actually expand in overall length by several inches requiring constant adjusting during harvesting operations to take up the slack created. If one of the metal pieces is broken and becomes entrained with the crop that is being harvested, the dislodged part may seriously damage or cause a lockup of downstream processing mechanisms in the harvester including knife cylinders, high speed fans, etc. A major performance limitation of the mechanical chain configuration of the prior art is that it is limited to low speed operation and is objectionably noisy. In addition, there is continuous maintenance required on such mechanical chains, in that the need for lubrication is constant, and metal parts must periodically be replaced. The metallic chains are also very heavy and add to the weight of the harvester.
Flexible belts having lugs on one surface adapted for positive driving by a sprocket and having molded transverse ribs on the upper surface are known for crop gathering use where a pair of belts are positioned to entrap grain stalks between the opposed ribbed surfaces of the belts. Such belts suffer the disadvantage that when a transverse cleat is damaged, or ripped off during harvesting operations, the entire belt must be replaced. Such an occurrence is not unusual when crop residue, rocks or debris become jammed in the conveyor. A belt having the transverse molded ribs covering the complete width of the conveying mechanism in a combine adds considerable weight to the harvester and is very expensive to produce as an endless belt without mechanical splice.